The purpose of this 2-part paper was to describe individuals' health information-seeking behavior (HISB) patterns that emerged from our grounded theory study. Thirty individual interviews and 8 focus groups were conducted with individuals diagnosed with cancer. Analysis was characterized by constant comparison diagram, an evolving coding scheme, and ultimately the generation of a grounded theory of HISB patterns. Five HISB patterns were identified: (1) intense information seeking-a keen interest in detailed cancer information; (2) complementary information seeking--the process of getting "good enough" cancer information; (3) fortuitous information seeking--the search for cancer information mainly from others diagnosed with cancer; (4) minimal information seeking--a limited interest for cancer information; and (5) guarded information seeking--the avoidance of some cancer information. Part 1 focuses on describing the first 3 HISB patterns considered to illustrate variations in active information seeking. Each pattern is explained, including the type, amount, and sources of information sought. This analysis documents variations in active HISB often overlooked in the cancer literature. Findings may assist healthcare professionals in tailoring their informational interventions according to a patient's preferred HISB pattern. Furthermore, findings may inform the refinement of instruments measuring HISB to include variations in active information seeking.